1. Field of the Invention
The present invention relates to a sodium-cooled fast reactor for nuclear power generation, and more particularly, to a water leakage-acoustic sensing method and apparatus in a steam generator of a sodium-cooled fast reactor using a standard deviation of an octave band.
2. Description of Related Art
In nuclear power generation, materials with a nucleus possessing tremendous energy, such as uranium, are used. Various types of reactors such as a pressurized water reactor (PWR), a heavy water reactor, a sodium-cooled fast reactor, and the like are used to slowly generate nuclear energy, generated when atomic nuclei are fissioned or fused, and to convert the nuclear energy into electric energy.
Currently, a sodium-cooled fast reactor is developed and used as a fast breeder reactor using liquid metals, for example, liquid sodium, as a coolant. In this instance, liquid metals are excellent in heat transfer and do not decelerate neutrons.
Since the sodium-cooled fast reactor has many neutrons generated by nuclear fission and little neutron absorption due to a liquid coolant, the sodium-cooled fast reactor has a high ratio of converting uranium 238 into plutonium 239. Accordingly, since a newly-produced fuel becomes more than a consumed fuel, a use efficiency of uranium may be significantly improved.
Since the sodium-cooled fast reactor generates the nuclear fission by the quick neutrons and generates a high-density heat output, compared with a light water reactor, the sodium-cooled fast reactor uses the liquid sodium that does not decelerate and absorb the neutrons and easily transfers heat.
In France, the first sodium-cooled fast reactor of 250,000 kW has already been operating since 1974, and ‘Super Phenix’ being a large reactor of 1,240,000 kW has operated since 1989. Also, in Japan, ‘Joyo’ of 100,000 kW being an experimental reactor reached a threshold in 1972, and ‘Monju’ of 280,000 kW subsequently performed initial power transmission on Aug. 29, 1995, however, operation of ‘Monju’ are currently stopped due to a sodium leakage accident. In the Republic of Korea, its own development and international joint research are under way nationwide for practical use of the sodium-cooled fast reactor, and research development for securing a base technology is under way targeting commercialization after 2030.
However, a steam generator of the sodium-cooled fast reactor using liquid sodium as the coolant uses water for generating steam, and an accidental crack in a heat pipe of the steam generator may occur due to corrosions or thermal imbalance. Since water (steam) flows into sodium by such crack and sodium reacts with water, serious damage to a heat pipe tube of the steam generator is caused.